Stripe is a financial infrastructure company that lets businesses accept payments and run their money operations through a set of developer-friendly APIs. Founded in 2010 by Irish brothers Patrick and John Collison, it powers everything from indie side projects to Fortune 500 checkouts, processing more than $1.9 trillion in payments in 2025. Beyond core card processing, Stripe offers billing, fraud protection, business incorporation, card issuing, tax automation, and banking-as-a-service, positioning itself as the economic layer of the internet.
Flodesk is a bootstrapped, San Francisco-based email marketing and e-commerce platform built for creators, coaches, and small businesses that care about design. Founded in 2019 by Rebecca Shostak, Martha Bitar, and Trong Dong, it pairs an intuitive drag-and-drop email builder with beautiful templates, automations, forms, link-in-bio pages, and a no-fee Stripe checkout. The company grew profitably to more than $36 million in annual recurring revenue and over 100,000 paying customers without taking outside funding, and in 2026 it launched Flodesk Studio, an AI design app that turns hours of email creation into minutes.
Hubla is a Brazilian creator-economy platform that lets creators sell and manage digital products - online courses, memberships, mentorships, e-books and paid WhatsApp/Telegram communities - through an all-in-one checkout, payments and member-management system. Founded in 2020 as ChatPay and rebranded to Hubla in late 2021, the São Paulo company processes payments (PIX, card, boleto) and takes a fee on each sale. Backed by Kaszek and Y Combinator, it has grown into one of the country's larger 'Shopify for creators' players and is now leaning into AI sales agents.
Sam O'Keefe is the co-founder and CEO of Flex, the San Francisco fintech often called 'Stripe for HSA/FSA payments.' Flex lets health and wellness brands accept the roughly $150 billion of tax-advantaged health-account money that Americans leave sitting unused every year, turning a confusing benefits process into a one-tap checkout. A two-time Y Combinator founder who previously built fraud and risk software at Unit21 and led startup programs at Google, O'Keefe raised a $15M Series A in September 2025 to make 'pay with HSA/FSA' as ordinary at checkout as PayPal.
Kudos is an AI-powered smart wallet that tells you which credit card to use at checkout to squeeze the most rewards out of cards you already carry. Built as a free browser extension and mobile app, it supports 3,000+ cards across more than a million sites, layers on extra rewards through its Kudos Boost partner network, and keeps track of card benefits so members don't have to. Founded in 2021 by ex-Google Pay and Affirm product leaders, the Los Angeles company crossed 400,000 members and raised a $10.2M Series A led by QED Investors in 2024.
Fun (fun.xyz) is a payments infrastructure company that moves money on and off blockchains for modern fintech apps. Its rails power deposits, withdrawals, orchestration, and checkout for platforms like Polymarket, Aave, and Lighter - processing more than $18 billion a year. Founded in 2022 by Stanford dropout Alex Fine, the company raised a $72 million Series A in early 2026 led by Multicoin Capital and SignalFire, aiming to be 'the front door' to the new digital economy.
Bolt is a San Francisco fintech building a one-click checkout network for online retailers. It connects merchants and shoppers through a single, cross-site identity, layering payments, fraud prevention, and AI-personalized flows on top. After a turbulent stretch following its 2022 peak, Bolt has been rebuilding through partnerships with Palantir, Klarna, Affirm, and Checkout.com, and a return of founder Ryan Breslow to the CEO seat.